BACKGROUND:Ankle fracture complicated with deltoid ligament injury is clinically common,and one stage repair of deltoid ligament with internal fracture fixation has gradually become a main therapeutic method,which can significantly reduce the long-term complications of ankle joint.In recent years,new progress has been made in anatomical structure characteristics and dynamic biomechanical research of deltoid ligament,thus greatly improving repairing techniques for injury in the deep layer of deltoid ligament,but there are still some controversies.OBJECTIVE:To explore the clinical efficacy of suture anchor and medial malleolus repair in the treatment of ankle joint fractures with the deep layer of deltoid ligament.METHODS:A total of 56 patients with ankle joint fractures and complete fracture of the deep and superficial layer of deltoid ligament treated in Affiliated Haikou Hospital,Xiangya School of Medicine,Central South University from January 2017 to January 2022 were selected,and they were divided into two groups according to different treatment methods in repairing the deep layer of deltoid ligament with suture anchor:suture anchor repair group(n=32)and medial malleolus repair group(n=24).The medial clear space of ankle joint and American Orthopedic Foot and Ankle Society Score of patients in the two groups were evaluated before and after operative treatment.RESULTS AND CONCLUSION:(1)All the 56 patients finished the surgery smoothly and were followed up for more than 12 months after operation.Their ankle fracture healed,and the time for fracture healing was 8-12 weeks,with a mean of 10.5 weeks.(2)The medial clear space of ankle joint in the two groups 12 months after operation was remarkably narrower than that before operation,and the difference was statistically significant(P＜0.001).The medial clear space of ankle joint in the two groups maintained a normal range 12 months after operation,and there was no statistically significant difference between the two groups(P＞0.05).(3)The AOFAS scale of patients in the two groups 6 and 12 months after operation was obviously bigger than that before operation(P＜0.001),but there was no statistically significant difference in the American Orthopedic Foot and Ankle Society Score of patients between the two groups at corresponding time points(P＞0.05).(4)It is concluded that both suture anchor and medial malleolus repair in the treatment of injury in the deep layer of deltoid ligament can recover the medial clear space of ankle joint,effectively keep the stability of ankle,and thus achieve good clinical efficacy.

Objective:To explore the mechanisms of action of Huanglian Jiedu decoction combined with Xijiao Dihuang decoction (HLJDT-XJDH) in regulating fibroblasts in the treatment of psoriasis. Methods:A mouse model of psoriasis was established by topical application of imiquimod 5% cream on the shaved back; HLJDT-XJDH at different doses of 7.7 and 30.6 g/kg was administered via gavage for intervention, and methotrexate (2 mg/kg) served as a positive control; after 7 days, the severity of skin lesions was assessed using the psoriasis area and severity index (PASI), while histopathological changes of skin tissues were evaluated using hematoxylin-eosin (HE) staining and Baker scoring. For in vitro experiments, fibroblasts were divided into a control group, a model group, a low-dose (5% drug-containing serum) intervention group, and a high-dose (20% drug-containing serum) intervention group; cells in the control group were cultured with 20% normal rat serum for 24 hours; in the model group, cells cultured with 20% normal rat serum were stimulated with 5 ng/ml tumor necrosis factor (TNF) -α and 50 ng/ml interleukin (IL) -17A for 24 hours to mimic fibroblasts during the occurrence of psoriasis; cells in the low- and high-dose intervention groups received the same stimulation as the model group, and were cultured for 24 hours with 5% and 20% HLJDT-XJDH-containing serum, respectively, but not with the 20% normal rat serum. After the above treatment, these cells were co-cultured with keratinocytes (HaCaT cells) using a Transwell system. In addition, on the basis of the control group, fibroblasts were divided into the model group, 20% drug-containing serum intervention group, and 20% drug-containing serum intervention + OE-SFRP2 group; TNF-α and IL-17A were used to stimulate the cells to simulate the psoriatic state; the treatment in the 20% drug-containing serum intervention group was carried out as previously described; in the 20% drug-containing serum intervention + OE-SFRP2 group, cells were transfected with the vector for 48 hours to establish an overexpression model, followed by culture with 20% drug-containing serum for 24 hours, without co-culture with HaCaT cells.. Cell counting kit-8 (CCK-8) assay was performed to assess cell viability, flow cytometry to measure apoptosis rates, enzyme-linked immunosorbent assay (ELISA) to detect levels of inflammatory cytokines (TNF-α, IL-1β, IL-6) as well as chemokine ligand (CXCL) 1 and CXCL12 in mouse serum or cell culture supernatant, qPCR to determine the mRNA expression of inflammatory cytokines, chemokines, cell cycle- and proliferation-related factors, as well as SFRP2 in mouse skin tissues or cells, and Western blot analysis to determine the protein expression of SFRP2, Wnt3a, and β-catenin in fibroblasts. One-way analysis of variance was employed for intergroup comparisons, and post-hoc analysis was conducted using Tukey's test. Results:In vivo mouse experiments showed that compared with the normal control group, the model group exhibited typical psoriatic characteristics in skin morphology, including significant inflammatory infiltration in skin tissues and marked epidermal thickening; compared with the normal control group, the serum levels of TNF-α (531.16 ± 28.27 pg/ml vs. 239.58 ± 10.39 pg/ml), IL-1β (111.40 ± 5.16 pg/ml vs. 80.35 ± 3.87 pg/ml), and IL-6 (109.17 ± 4.84 pg/ml vs. 71.73 ± 2.04 pg/ml) significantly increased in the model group, along with their mRNA expression levels in mouse skin tissues (all P < 0.001) ; compared with the model group, the treatment group showed alleviated psoriatic manifestations, and significant reductions in the levels of inflammatory factors TNF-α (low-dose, high-dose, and positive control groups: 420.80 ± 29.30 pg/ml, 322.33 ± 9.40 pg/ml, 322.97 ± 12.16 pg/ml, respectively), IL-1β (98.69 ± 4.49 pg/ml, 89.02 ± 1.56 pg/ml, 88.88 ± 2.08 pg/ml, respectively), and IL-6 (94.07 ± 3.76 pg/ml, 80.54 ± 3.30 pg/ml, 83.21 ± 3.18 pg/ml, respectively), as well as in their mRNA expression levels (all P < 0.001). In in vitro fibroblast experiments, compared with the control group, the model group exhibited a significant elevation in the supernatant levels of IL-1β (126.42 ± 3.56 pg/ml vs. 34.81 ± 0.44 pg/ml), IL-6 (459.44 ± 9.35 pg/ml vs. 115.51 ± 7.26 pg/ml), CXCL1 (2 434.88 ± 127.63 pg/ml vs. 762.85 ± 30.60 pg/ml) and CXCL12 (3 542.14 ± 35.86 pg/ml vs. 2 095.86 ± 45.12 pg/ml), the expression levels of their mRNAs (all P < 0.001), as well as the protein expression levels of SFRP2, Wnt3a, and β-catenin; after intervention with HLJDT-XJDH-containing serum, all the above indices significantly decreased (all P < 0.001). However, when 20% drug-containing serum intervention was administered simultaneously, the expression of inflammatory factors and chemokines in fibroblasts was significantly higher in the SFRP2 overexpression group than in the non-overexpression group (all P < 0.01). When fibroblasts were co-cultured with HaCaT cells, the model group showed significantly increased cell viability but a decreased apoptosis rate of HaCaT cells compared with the control group, while the low- and high-dose intervention groups showed significantly decreased cell viability but increased apoptosis rates of HaCaT cells compared with the model group (all P < 0.05) . Conclusion:HLJDT-XJDH may exert therapeutic effects in psoriasis by downregulating the SFRP2/Wnt/β-catenin signaling pathway, thereby inhibiting fibroblast activation and inflammatory process, which subsequently suppresses the proliferation of keratinocytes and the activation of inflammatory cells.

BACKGROUND:Ankle fracture complicated with deltoid ligament injury is clinically common,and one stage repair of deltoid ligament with internal fracture fixation has gradually become a main therapeutic method,which can significantly reduce the long-term complications of ankle joint.In recent years,new progress has been made in anatomical structure characteristics and dynamic biomechanical research of deltoid ligament,thus greatly improving repairing techniques for injury in the deep layer of deltoid ligament,but there are still some controversies.OBJECTIVE:To explore the clinical efficacy of suture anchor and medial malleolus repair in the treatment of ankle joint fractures with the deep layer of deltoid ligament.METHODS:A total of 56 patients with ankle joint fractures and complete fracture of the deep and superficial layer of deltoid ligament treated in Affiliated Haikou Hospital,Xiangya School of Medicine,Central South University from January 2017 to January 2022 were selected,and they were divided into two groups according to different treatment methods in repairing the deep layer of deltoid ligament with suture anchor:suture anchor repair group(n=32)and medial malleolus repair group(n=24).The medial clear space of ankle joint and American Orthopedic Foot and Ankle Society Score of patients in the two groups were evaluated before and after operative treatment.RESULTS AND CONCLUSION:(1)All the 56 patients finished the surgery smoothly and were followed up for more than 12 months after operation.Their ankle fracture healed,and the time for fracture healing was 8-12 weeks,with a mean of 10.5 weeks.(2)The medial clear space of ankle joint in the two groups 12 months after operation was remarkably narrower than that before operation,and the difference was statistically significant(P＜0.001).The medial clear space of ankle joint in the two groups maintained a normal range 12 months after operation,and there was no statistically significant difference between the two groups(P＞0.05).(3)The AOFAS scale of patients in the two groups 6 and 12 months after operation was obviously bigger than that before operation(P＜0.001),but there was no statistically significant difference in the American Orthopedic Foot and Ankle Society Score of patients between the two groups at corresponding time points(P＞0.05).(4)It is concluded that both suture anchor and medial malleolus repair in the treatment of injury in the deep layer of deltoid ligament can recover the medial clear space of ankle joint,effectively keep the stability of ankle,and thus achieve good clinical efficacy.

Objective:To explore the mechanisms of action of Huanglian Jiedu decoction combined with Xijiao Dihuang decoction (HLJDT-XJDH) in regulating fibroblasts in the treatment of psoriasis. Methods:A mouse model of psoriasis was established by topical application of imiquimod 5% cream on the shaved back; HLJDT-XJDH at different doses of 7.7 and 30.6 g/kg was administered via gavage for intervention, and methotrexate (2 mg/kg) served as a positive control; after 7 days, the severity of skin lesions was assessed using the psoriasis area and severity index (PASI), while histopathological changes of skin tissues were evaluated using hematoxylin-eosin (HE) staining and Baker scoring. For in vitro experiments, fibroblasts were divided into a control group, a model group, a low-dose (5% drug-containing serum) intervention group, and a high-dose (20% drug-containing serum) intervention group; cells in the control group were cultured with 20% normal rat serum for 24 hours; in the model group, cells cultured with 20% normal rat serum were stimulated with 5 ng/ml tumor necrosis factor (TNF) -α and 50 ng/ml interleukin (IL) -17A for 24 hours to mimic fibroblasts during the occurrence of psoriasis; cells in the low- and high-dose intervention groups received the same stimulation as the model group, and were cultured for 24 hours with 5% and 20% HLJDT-XJDH-containing serum, respectively, but not with the 20% normal rat serum. After the above treatment, these cells were co-cultured with keratinocytes (HaCaT cells) using a Transwell system. In addition, on the basis of the control group, fibroblasts were divided into the model group, 20% drug-containing serum intervention group, and 20% drug-containing serum intervention + OE-SFRP2 group; TNF-α and IL-17A were used to stimulate the cells to simulate the psoriatic state; the treatment in the 20% drug-containing serum intervention group was carried out as previously described; in the 20% drug-containing serum intervention + OE-SFRP2 group, cells were transfected with the vector for 48 hours to establish an overexpression model, followed by culture with 20% drug-containing serum for 24 hours, without co-culture with HaCaT cells.. Cell counting kit-8 (CCK-8) assay was performed to assess cell viability, flow cytometry to measure apoptosis rates, enzyme-linked immunosorbent assay (ELISA) to detect levels of inflammatory cytokines (TNF-α, IL-1β, IL-6) as well as chemokine ligand (CXCL) 1 and CXCL12 in mouse serum or cell culture supernatant, qPCR to determine the mRNA expression of inflammatory cytokines, chemokines, cell cycle- and proliferation-related factors, as well as SFRP2 in mouse skin tissues or cells, and Western blot analysis to determine the protein expression of SFRP2, Wnt3a, and β-catenin in fibroblasts. One-way analysis of variance was employed for intergroup comparisons, and post-hoc analysis was conducted using Tukey's test. Results:In vivo mouse experiments showed that compared with the normal control group, the model group exhibited typical psoriatic characteristics in skin morphology, including significant inflammatory infiltration in skin tissues and marked epidermal thickening; compared with the normal control group, the serum levels of TNF-α (531.16 ± 28.27 pg/ml vs. 239.58 ± 10.39 pg/ml), IL-1β (111.40 ± 5.16 pg/ml vs. 80.35 ± 3.87 pg/ml), and IL-6 (109.17 ± 4.84 pg/ml vs. 71.73 ± 2.04 pg/ml) significantly increased in the model group, along with their mRNA expression levels in mouse skin tissues (all P < 0.001) ; compared with the model group, the treatment group showed alleviated psoriatic manifestations, and significant reductions in the levels of inflammatory factors TNF-α (low-dose, high-dose, and positive control groups: 420.80 ± 29.30 pg/ml, 322.33 ± 9.40 pg/ml, 322.97 ± 12.16 pg/ml, respectively), IL-1β (98.69 ± 4.49 pg/ml, 89.02 ± 1.56 pg/ml, 88.88 ± 2.08 pg/ml, respectively), and IL-6 (94.07 ± 3.76 pg/ml, 80.54 ± 3.30 pg/ml, 83.21 ± 3.18 pg/ml, respectively), as well as in their mRNA expression levels (all P < 0.001). In in vitro fibroblast experiments, compared with the control group, the model group exhibited a significant elevation in the supernatant levels of IL-1β (126.42 ± 3.56 pg/ml vs. 34.81 ± 0.44 pg/ml), IL-6 (459.44 ± 9.35 pg/ml vs. 115.51 ± 7.26 pg/ml), CXCL1 (2 434.88 ± 127.63 pg/ml vs. 762.85 ± 30.60 pg/ml) and CXCL12 (3 542.14 ± 35.86 pg/ml vs. 2 095.86 ± 45.12 pg/ml), the expression levels of their mRNAs (all P < 0.001), as well as the protein expression levels of SFRP2, Wnt3a, and β-catenin; after intervention with HLJDT-XJDH-containing serum, all the above indices significantly decreased (all P < 0.001). However, when 20% drug-containing serum intervention was administered simultaneously, the expression of inflammatory factors and chemokines in fibroblasts was significantly higher in the SFRP2 overexpression group than in the non-overexpression group (all P < 0.01). When fibroblasts were co-cultured with HaCaT cells, the model group showed significantly increased cell viability but a decreased apoptosis rate of HaCaT cells compared with the control group, while the low- and high-dose intervention groups showed significantly decreased cell viability but increased apoptosis rates of HaCaT cells compared with the model group (all P < 0.05) . Conclusion:HLJDT-XJDH may exert therapeutic effects in psoriasis by downregulating the SFRP2/Wnt/β-catenin signaling pathway, thereby inhibiting fibroblast activation and inflammatory process, which subsequently suppresses the proliferation of keratinocytes and the activation of inflammatory cells.

【Objective】 To evaluate and analyze the impact of COVID-19 epidemic on inventory of red blood cells (RBCs)in local and municipal blood stations in China, and to provide reference for the management of public health emergencies. 【Methods】 Relevant data from 2018 to 2021 were collected, and the differences in the volume of qualified RBCs, the usage efficiency of inventory RBCs, the average daily distribution of RBCs,the blood distribution rate of RBCs prepared by 400 mL whole blood, the difference in the average storage days of RBCs at the time of distribution, the average daily inventory of RBCs and the time of the average daily inventory of RBCs to maintain the distribution in 24 local and municipal blood stations in China during the COVID-19 epidemic and non-epidemic periods were retrospectively analyzed. 【Results】 Compared with non-epidemic periods, the volume of qualified RBCs [(117 525.979 ±52 203.175)U] and the average daily distribution of RBCs [( 156. 468 ± 70. 186) U ] increased significantly, but the usage efficiency of inventory RBCs decreased(97.24%±0.51%) significantly (P<0.05).There was no significant difference in the blood distribution rate of RBCs prepared by 400 mL whole blood(73.88%±20.30%), the average storage days of RBCs distribution(13.040 ±3.486), the average daily stock quantity of RBCs[(2 280.542 ±1 446.538) U ] and the time of the average daily inventory of RBCs to maintain the distribution[(15.062 ±7.453) d] (P>0.5). 【Conclusion】 During the COVID-19 epidemic, the inventory management of RBCs operated well, the overall inventory remained relatively stable, the stock composition and storage period showed no significant change.

【Objective】 To analyze the basic characteristics of whole blood donors from blood stations before and after the outbreak of COVID-19. 【Methods】 After excluding invalid data, data related to the basic characteristics of whole blood donors collected from 26 blood stations in China during 2018 to 2021 were statistically analyzed, including the trend of total whole blood donors, the number of repeated blood donors, the frequency of blood donation, the average age of donors and the recruitment of first-time blood donors. 【Results】 Affected by the epidemic, 8 out of 14 indicators were with large variations, accounting for 57%. The overall growth rate of total whole blood donors during the epidemic was higher than before the epidemic (P<0.05).The number of repeated blood donors has shown an increased trend, with a higher number during the epidemic than before (P<0.05). The frequency of blood donation was lower during the epidemic than before(P<0.05).Average ages of blood donors and female blood donors fluctuated widely during the epidemic, both higher than those before the epidemic(P<0.05).The donation rate of first-time blood donors <25 years old and ≥25 years old varied widely and irregularly during the epidemic (both P<0.05). The percentage of first-time blood donors fluctuated irregularly during the epidemic, with overall percentage lower than that before the epidemic(P<0.05). 【Conclusion】 Whole blood donors from 26 blood stations increased after the outbreak of COVID-19, and some indicators in certain areas showed significant fluctuations during the epidemic.

Objective:To analyze the fail mode of neoadjuvant therapy combined with surgery for locally advanced esophageal squamous cell carcinoma (ESCC) after long-term follow-up.Methods:Clinical data of consecutive 238 patients with locally advanced resectable ESCC who underwent neoadjuvant therapy combined with surgery in Zhejiang Cancer Hospital from September 2012 to October 2019 were retrospectively analyzed. The failure mode in the whole cohort was analyzed after long-term follow-up. The overall survival (OS) and disease free survival (DFS) rates were analyzed by Kaplan-Meier method. Survival differences were determined by log-rank test.Results:The pathological complete response (pCR) rate was 42.0% in 238 patients. After a median follow-up of 46.1 months, tumor progression occurred in 96 patients (40.3%), including 25 patients (10.5%) with local recurrence, 61 patients (25.6%) with distant metastases, and 10 patients (4.2%) with simultaneous local recurrence and distant metastases. The median OS and DFS were 64.7 months and 49.9 months. And the 3-, 5-, and 7-year OS and DFS rates were 70.0%, 52.8%, 36.4% and 63.5%, 42.5%, and 30.0%, respectively. The 3-, 5-, and 7-year locoregional recurrence-free survival rates and distant metastasis-free survival rates were 86.0%, 71.4%, 61.2% and 70.6%, 55.9%, 43.0%. Compared with non-pCR patients, the overall progression rate and distant metastasis rate of pCR patients were lower (26.0% vs. 50.7%, 16.0% vs. 32.6%, both P<0.05). And the 3-, 5-, and 7-year OS (83.0% vs. 60.2%, 69.7% vs. 41.7%, 50.4% vs. 27.7%, all P<0.001) and DFS rates (80.4% vs. 51.4%, 63.9% vs. 31.2%, 45.9% vs. 20.3%, all P<0.001) were significantly better in pCR patients. Conclusions:Distant metastasis is the main failure mode of patients with locally advanced ESCC after neoadjuvant therapy. Patients with postoperative pCR can achieve better long-term survival.

Objective:To analyze the failure patterns and survival after stereotactic body radiotherapy (SBRT) in patients with T 1-2N 0M 0 non-small cell lung carcinoma (NSCLC). Methods:Clinical data of early-stage NSCLC patients who received SBRT at Zhejiang Cancer Hospital from January 2012 to September 2018 were retrospectively analyzed. The primary observed endpoint was the pattern of disease progression, which was divided into intra-field recurrence, regional lymph node recurrence and distant metastasis. Overall survival (OS) and progression-free survival (PFS) were calculated by Kaplan-Meier method. Univariate analysis was conducted by log-rank test, and multivariate analysis was performed by Cox's model.Results:A total of 147 patients with 156 lesions were included. The median follow-up time was 44.0 months (16.5-95.5 months). A total of 57 patients (38.8%) progressed: 14 patients (24.5%) had recurrence with the 1-, 3-, and 5-year local recurrence rates of 2.0%, 10.9%, and 14.3%, respectively; 36 patients (63.2%) had Distant metastasis with the 1-, 3- and 5-year distant metastasis rates of 12.2%, 22.4% and 28.6%, respectively; and 7 patients (12.3%) had recurrence complicated with distant metastasis. The 3-, 5- and 7-year OS rates were 80.5%, 64.2% and 49.9% for all patients, respectively. The median OS was 78.4 months. The 3-, 5- and 7-year PFS rates were 64.8%,49.5% and 41.5%, with a median PFS of 57.9 months (95% CI: 42.3-73.5 months). Univariate and multivariate analyses showed that biologically equivalent dose and age were the factors affecting the efficacy of SBRT (both P<0.05). Conclusion:Distant metastasis is the main failure pattern in patients with T 1-2N 0M 0 NSCLC after SBRT. High-risk population should be selected for further systematic treatment to improve the efficacy.

Objective:To explore the risk factors related to acute rejection (AR) after pediatric kidney transplantation (KT).Methods:Retrospective analysis was performed for 189 pediatric KT recipients from September 2011 to August 2022.They were divided into two groups of AR (n=33) and non-AR (n=156).Univariate and multivariate Logistic regression analyses were performed for identifying potential risk factors of AR.And the effects of AR on graft function and survival were also examined.Results:During follow-ups, a total of 33(17.5%) patients developed AR with a 1-year cumulative incidence of AR of 16.9%(32/189).Univariate analysis revealed that median time on dialysis was longer in AR group than that in non-AR group (19 vs. 11 months, P=0.034).Median age of donors (12 vs. 24 months, P=0.033), median weight of donors (9.5 vs. 12 kg, P=0.025) and median donor/recipient body weight ratio (0.36 vs. 0.50, P=0.005) were lower in AR group than those in non-AR group.And the proportion of subtherapeutic tacrolimus (TAC) trough level was higher in AR group than that in non-AR group (45.5% vs. 21.2%, P=0.004).Multivariate regression analysis indicated that subtherapeutic TAC trough level was an independent risk factor for AR ( OR=2.977, 95% CI: 1.314-6.743, P=0.009).At the last follow-up, serum creatinine and eGFR were (78.4±24.3) vs. (74.6±24.7) μmol/L and (85.3±26.3) vs. (89.5±24.2) ml·min -1·1.73 m -2 in AR and non-AR groups respectively.There were no significant differences.1/5-year patient survival rate was both 97% in AR group and both 99.4% in non-AR group; 1/5-year graft survival rate both 90.9% in AR group and was 98.1% and 97.4% in non-AR group.No significant inter-group differences existed in patient and graft survival. Conclusions:Although an occurrence of early AR does not negatively impact graft outcomes, the incidence of AR remains high after pediatric KT.Therefore prompt diagnosis and treatment of AR should be strengthened.

New threats posed by the emerging circulating variants of SARS-CoV-2 highlight the need to find conserved neutralizing epitopes for therapeutic antibodies and efficient vaccine design. Here, we identified a receptor-binding domain (RBD)-binding antibody, XG014, which potently neutralizes β-coronavirus lineage B (β-CoV-B), including SARS-CoV-2, its circulating variants, SARS-CoV and bat SARSr-CoV WIV1. Interestingly, antibody family members competing with XG014 binding show reduced levels of cross-reactivity and induce antibody-dependent SARS-CoV-2 spike (S) protein-mediated cell-cell fusion, suggesting a unique mode of recognition by XG014. Structural analyses reveal that XG014 recognizes a conserved epitope outside the ACE2 binding site and completely locks RBD in the non-functional "down" conformation, while its family member XG005 directly competes with ACE2 binding and position the RBD "up". Single administration of XG014 is effective in protection against and therapy of SARS-CoV-2 infection in vivo. Our findings suggest the potential to develop XG014 as pan-β-CoV-B therapeutics and the importance of the XG014 conserved antigenic epitope for designing broadly protective vaccines against β-CoV-B and newly emerging SARS-CoV-2 variants of concern.
Angiotensin-Converting Enzyme 2 ; Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 ; Epitopes ; Humans ; SARS-CoV-2/genetics* ; Spike Glycoprotein, Coronavirus/genetics*